This photo essay is part of a series on the planet’s major ecosystems, a topic that will be discussed at the Global Landscapes Forum New York on 28 September.
Drylands are areas that suffer from high water scarcity, mainly due to limited rainfall and high temperatures, as well as frequent droughts and heatwaves. They cover 41 percent of the planet’s land area and are found on every continent, though they are especially prevalent in Asia and Africa.
The climate places significant constraints on agriculture, livestock grazing and foraging in dryland areas. Despite these limitations, drylands are home to about 2 billion people globally and provide half of the world’s livestock and 44 percent of the world’s cultivated systems.
Despite their inhospitable climate, drylands support high levels of biodiversity, which in turn help maintain soil fertility and moisture to support agriculture and prevent drought. The loss of this biodiversity contributes to land degradation. In the context of drylands, degradation is also known as desertification.
Drylands are particularly vulnerable to climatic variations and climate change as well as damaging human activities such as deforestation and overgrazing. This is because dryland soils have relatively low fertility and are particularly susceptible to erosion and nutrient loss.
Rangelands are ecosystems that are primarily covered by shrubs and grasses. Sometimes also classifying as drylands, they can include prairies, steppes, desert shrublands, shrub woodlands, savannas and tundras, and they cover 40 to 50 percent of the Earth’s land area, spread across every continent except Antarctica.
Rangelands provide a variety of benefits to both biodiversity and human livelihoods, including serving as watersheds, carbon sinks, and habitats for native wildlife. They are also central to pastoralism, the mobile or sedentary practice of raising livestock. Pastoral livelihoods remain widespread in Africa, western Asia and parts of South America.
One of the main issues affecting both drylands and rangelands is land degradation, which reduces the biological and economic productivity of the land. In rangelands, degradation has made it more difficult for mobile pastoralists to adapt to changing conditions as they migrate across climatic zones.
At least 25 percent of drylands globally have already been degraded, affecting 250 million people, and up to 1 billion people could be at risk in the near future.
Read the rest of our ‘fast facts’ series on ecosystems below.